Twenty sockets do the work. The rest is drawer filler

Quick answer: Buy a 3/8-inch drive set with metric 8 through 19 mm and standard 1/4 through 3/4 inch, in 6-point. Add a 1/2-inch breaker bar and impact sockets for your lug nuts. Ignore the piece count on the box.

The number on the box is a sales trick

Open any 200-piece set. Count the sockets. It's usually around fifty.

The rest is bit drivers, extension bars, adapters, and sockets in sizes you'll touch once a decade. The count is there to make a seventy-dollar case look like a steal. It isn't a lie, exactly. It's just not the number that matters.

What matters is whether the 10 mm is in the case when you're under the dash at nine at night. Which brings us to the 10 mm.

The sizes that earn their drawer space

Most work on cars, mowers, bikes, appliances, and furniture comes down to a short list.

Metric, 3/8-inch drive:

• 8, 10, 12, 13, 14, 17, 19 mm. These seven cover most of what you'll loosen on a modern car or small engine.
• 10 mm is the famous one. It holds battery terminals, trim, and half the brackets in an engine bay. Buy a second one. You're going to lose the first.
• 15, 16, 18 mm turn up now and then, especially on Japanese cars. They're worth owning, but they're second string.

Standard (SAE), 3/8-inch drive:

• 3/8, 7/16, 1/2, 9/16, 5/8, 3/4 inch. That's the American-made lawn equipment, trailer, and farm-tool list.
• 11/32 and the other odd sixteenths and thirty-seconds are real sizes. They're also the ones that sit untouched. Own them if they come in the set. Don't pay extra for them.

Big sockets for the 1/2-inch drive:

• Lug nut size for your vehicle. Most passenger cars run 19 to 21 mm. Many trucks run 22 mm or larger. Check your owner's manual or put a socket on the nut and see.
• Spark plug socket, usually 5/8 inch or 13/16 inch, depending on the engine. Get the one with the rubber insert that grips the plug.

Three near-twins that will round off a bolt

Some metric and standard sizes sit almost on top of each other:

• 1/2 inch is 12.7 mm. A 13 mm socket will fit it, sloppy.
• 9/16 inch is 14.3 mm. A 14 mm will slip on, loosely.
• 3/4 inch is 19.05 mm. A 19 mm is almost a perfect fit, which makes it easy to forget you're using the wrong one.

Sloppy fit is how heads get rounded. If a socket slides on with any wiggle, stop and find the right one. Spend ten seconds on this and you save yourself an afternoon with an extractor.

What the drive sizes are actually for

You'll see three drive sizes in the store, and they aren't interchangeable.

1/4-inch drive is for small fasteners, roughly 4 to 14 mm. It's light and quick in tight spots. It's the wrong tool for anything stuck. Put real force on it and you'll strip the ratchet.

3/8-inch drive is the workhorse. If you buy one set, buy this one.

1/2-inch drive is for lug nuts, suspension bolts, and anything that takes muscle. A breaker bar in this size does the hard work. Don't use your ratchet as a pry bar. That's what the bar is for.

3/4-inch drive is for heavy equipment and big truck work. You probably don't need it. If you do, you'll know.

What the cheap set gets right and wrong

Be fair to the house brands. A set from a big-box line, such as Husky, Kobalt, or Pittsburgh from Harbor Freight, will turn most bolts you meet in a home garage. Sockets are simple. Steel with a hole is steel with a hole. As a rough ballpark, a decent 3/8-inch set runs from around forty to a hundred dollars, and prices move, so check before you buy.

Where the cheap set tends to fall short:

• The ratchet. It's the first thing to fail. A cheap one clicks, slips, or feels gritty within a couple of years of real use. This is the part worth upgrading.
• The finish and markings. Etched or stamped sizes wear off, and the chrome can chip. That makes it hard to read the size in bad light.
• Fit tolerance. Sloppier sockets round off more bolts.

Step up to Gearwrench or Tekton and you're usually in the eighty-to-two-hundred-dollar range for a good 3/8-inch set. That's where most people should land. Snap-on, Matco, and Mac sell the best, and they cost several times as much. If you wrench for a living, fine. If you're changing oil and swapping a battery, you're paying for a truck-mounted service you'll never use.

Spend where it counts

Three things deserve better steel than the rest of the set.

1. A good ratchet. Sixty to a hundred twenty dollars on a quality 3/8-inch, in a ballpark sense. This is the one you hold the most.
2. A 1/2-inch breaker bar, 18 to 24 inches long. A bar costs a fraction of a ratchet and saves it.
3. Impact sockets for lug nuts. They're thicker and darker than chrome ones. Chrome sockets can crack under an impact wrench, and flying chrome is a bad day. Buy the one size you need rather than a whole set.

Keep the chrome for hand tools and impacts for the gun. Don't mix them.

6-point beats 12-point for stuck bolts

A 12-point socket looks more flexible because it fits on a hex bolt at more angles. That's the selling point. The cost is that it grips the corners instead of the flats, and corners are what round off.

Buy 6-point as your default. Add a 12-point only for square-head fasteners, or tight spots where you can't swing the handle far.

Shallow sockets cover most work. Add deep sockets in the sizes you'll use most, usually 10, 13, 14, and 17 mm, for fasteners that sit on a long stud.

When to borrow or rent instead

Don't buy a $60 socket for a one-time job.

Axle nuts, harmonic balancer bolts, and some hub nuts run 30 to 36 mm or bigger. You'll use that socket once. Most major auto parts chains run a loan-a-tool program: you leave a deposit, take the tool home, and get the deposit back when you return it. Ask at the counter and check the current terms. For a big torque job, a rental or loaner is the right call. For the broader question, see The Tools You Should Rent and the Ones You Should Just Buy.

The weekend plan

Saturday morning, one hour. Dump every socket on a towel. Pull the ones you've actually used in the last year. Set the rest aside in a box.

Saturday afternoon. Check your gaps against the lists above. Write down the missing sizes, especially a second 10 mm, your lug nut size, and a breaker bar. Order or buy those, not a new set.

Sunday, one hour. Mount the working sockets on rails or in a tray, in size order, metric and standard on separate rows. Label the ends if the markings are faint. Put the bits and oddballs in a box on a high shelf.

The goal is twenty sockets you can grab without thinking. If you want the drawer, rail, and wall layout around them, Where Every Tool Goes and Why You'll Actually Put It Back covers that, and The 20 Tools Every Homeowner Needs and What to Pay for Each shows where sockets fit in the bigger kit.

Then do the part nobody does. After every job, count the sockets back onto the rail before you wipe your hands. A missing 10 mm is much easier to find ten seconds after you've put it down than ten days later.